According to the ADA acceptance program for posterior composite materials, occlusal wear should not exceed 250 mu during a five year period of clinical service. To determine this amount of wear, either comparison with standards or highly sophisticated and expensive techniques are used. The drawbacks with these techniques are that they are either too inaccurate or too complex to become generally accepted. In order to facilitate precise clinical wear determinations, at least within a few microns at any point on the occlusal surface, a shadow-moire technique is suggested to be evaluated and used together with computerized mapping. The first objective with this project is to find the right grating sizes in order to get precise but at the same time easy to read shadow-moire fringe patterns. The fringes will be recorded on photographic material and enlarged. By use of a digitizer, x-, y-, and z-coordinates will be determined for different points on the photograph of the tooth surface. By use of an available software for coordinate transformation, these points will be oriented relative to a reference plane which is determined from the values of three reference points. This information will then be treated with available software to produce computer graphics, on which variables such as volume between refernce plane and the surface of the restoration can be determined. Following the initial technique developmental section, studies will be conducted in order to determine how factors such as cusp slopes, cusp lengths, camera distortion, and distortion caused by the enlargement process influence the accuracy of the shadow moire technique. These determinations will be conducted on machined metal tooth dies with known geometry.